海角大神

A new study has answered one of comets' most enduring mysteries.

For the first time, scientists have been able to provide precise measurements and analysis of a comet. Of the through space, only eight have been visited by human technology. As a result, scientists' understanding of comets, while growing, , according to an European Space Agency press release.

Comets鈥� densities are low, according to most measurements. The low density has indicated the objects are highly porous, but left questions over whether that was the result of cavernous interiors or just a low-density composition.聽

A study published in the journal Science proves the inside of a comet consists of 鈥渕ostly dust and water ice 鈥� homogeneous and without large voids.鈥澛�

A team of scientists with the Rheinische Institut f眉r Umweltforschung an der Universit盲t zu K枚ln, Germany, came to this conclusion through an experiment measuring the gravitational pull of Comet 67P/Churyumov-Gerasimenko on The European Space Agency's Rosetta orbiter,聽by analyzing changes in the orbiter鈥檚 frequency. As a result of the Doppler effect, the radio frequency the orbiter was beaming to Earth would change when it was pulled by the gravity of the comet, allowing scientists to create a map of the gravitational field around the comet.

鈥淣ewton鈥檚 law of gravity tells us that the Rosetta spacecraft is basically pulled by everything,鈥� principial investigator Martin P盲tzold said in the release.聽

鈥溾�� This means that we had to remove the influence of the Sun, all the planets 鈥� from giant Jupiter to the dwarf planets 鈥� as well as large asteroids in the inner asteroid belt, on Rosetta鈥檚 motion, to leave just the influence of the comet. Thankfully, these effects are well understood and this is a standard procedure nowadays for spacecraft operations.鈥�

The analysis also required a touch of cosmic luck. Comet 67P/Churyumov-Gerasimenko has a double-lobe structure, which has allowed the team to gather much more accurate and precise measurements of the gravitational field, according to the release.

鈥淭he high porosity seems to be an inherent property of the nucleus material,鈥� the study concluded.

The Rosetta orbiter launched in March 2004 and embarked on a 10-year flight to deep space, where it rendezvoused with Comet 67P/Churyumov-Gerasimenko in 2014.

The Rosetta orbiter was accompanied on its trip by the Philae lander, which landed on the surface of the comet and collected information. The information was sent to Rosetta and the orbiter sent it to Earth. The European Space Agency lost contact with Philae in July. Attempts to reconnect with the lander have been unsuccessful.

Without any chance to reconnect with Philae, Rosetta鈥檚 mission will end in September 2016. The press release reports that the Rosetta orbiter will be 鈥済uided to a controlled impact on the surface of the comet.鈥�